When soft tissue tears away from bone, reattachment becomes necessary. Various devices, including sutures alone, screws, staples, wedges, and plugs have been used to secure soft tissue to bone. Recently, various types of suture anchors have been developed for this purpose. For example, U.S. Pat. No. 4,632,100 discloses a cylindrical suture anchor which includes a drill bit at a leading end for boring a hole in a bone. The drill bit at the leading end is followed by a flight of threads for securing the anchor into the hole bored in the bone by the drill bit. Another example is U.S. Pat. No. 5,370,662 which discloses a self-tapping suture anchor having a flight of threads around a solid body. Similarly, U.S. Pat. No. 5,156,616 discloses a suture anchor having an axial opening for holding a knotted piece of suture.
The devices disclosed in the above-cited patents anchor suture to bone, but require the surgeon to tie a knot in the suture arthroscopically in order to achieve fixation of the soft tissue to the bone. As a result, devices which do not require arthroscopic knot tying for fixation have been proposed. For example, U.S. Pat. No. 6,027,523, the disclosure of which is incorporated by reference herein, describes a suture anchor equipped with a tissue-fixation disk which does not require arthroscopic knot tying for fixation. The free ends of suture of the suture anchor are secured to the tissue-fixation disk by using knots on the top of the tissue-fixation disk, as well as a drop of polyacrylamide or similar cement material to secure the knots to the tissue-fixation disk.
It would be desirable to provide a suture anchor with an attached tissue-fixation disk which does not require multiple suture knots that are exposed on the upper surface of the tissue-fixation disk.